Organic light emitting diode display device

ABSTRACT

Disclosed is an organic light emitting diode display device. The disclosed organic light emitting diode display device includes an overcoat layer disposed on a substrate that is divided into an emissive area and a non-emissive area, and has multiple micro lenses in the emissive area and at least one depression in the non-emissive area. The organic light emitting diode display device further includes: a first electrode disposed on the overcoat layer, wherein the first electrode is disposed in the entire emissive area and in a part of the non-emissive area; a bank pattern disposed in the non-emissive area so as to be superposed on the depression; an organic light emitting layer disposed on the substrate; and a second electrode disposed on the organic light emitting layer. Accordingly, the organic light emitting diode display device may prevent light leakage.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No.10-2015-0152637, filed on Oct. 30, 2015, Korean Patent Application No.10-2016-0083121, filed on Jun. 30, 2016, and Korean Patent ApplicationNo. 10-2016-0137889, filed on Oct. 21, 2016, all of which are herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an organic light emitting diode displaydevice that includes a light-scattering layer having a pattern appliedthereto.

Description of the Prior Art

Organic light emitting diode display devices, which are self-lightemitting display devices, may be made lighter and slimmer since they donot need separate light sources, as opposed to liquid crystal displaydevices. Furthermore, organic light emitting diode display devices havebeen studied as next-generation display devices thanks to theirexcellent implementation of color, response speed, viewing angle, andcontrast ratio (CR), as well as advantages in power consumption by meansof low-voltage operation.

Light emitted from an organic light emitting layer of an organic lightemitting diode display device passes through multiple components of theorganic light emitting diode display device and exits from the organiclight emitting diode display device. However, a part of the lightemitted from the organic light emitting layer is confined in the organiclight emitting diode display device without being extracted therefrom.Accordingly, the light extraction efficiency of an organic lightemitting diode display device has come into question.

Particularly, in a bottom-emission type organic light emitting diodedisplay device among organic light emitting diode display devices, lightconfined in the organic light emitting diode display device due tototal-reflection or light-absorption by an anode electrode accounts foras much as about 50% of light emitted from an organic light emittinglayer, and light confined in the organic light emitting diode displaydevice due to total-reflection or light-absorption by a substrateaccounts for as much as about 30% of the light emitted from the organiclight emitting layer. As described above, about 80% of the light emittedfrom the organic light emitting layer is confined in the organic lightemitting diode display device, and only about 20% thereof is extractedfrom the organic light emitting diode display device, which leads to avery low light-extraction efficiency.

In order to enhance the light extraction efficiency of such an organiclight emitting diode display device, a method for attaching a micro lensarray (MLA) to the outside of a substrate of an organic light emittingdiode display device or a method for forming micro lenses on an overcoatlayer of an organic light emitting diode display device has beendeveloped.

However, by applying a micro lens array or micro lenses, light directedtoward an adjacent sub-pixel among light emitted from an organic lightemitting element travels along an overcoat layer on account of anadditional inclined surface generated by the micro lenses disposed onthe edge of an emissive area and reaches the adjacent sub-pixel emittinglight having a different color to cause a light leakage phenomenon.

SUMMARY OF THE INVENTION

In this background, an aspect of the present invention is to provide anorganic light emitting diode display device that includes alight-scattering layer having a pattern applied thereto, which canprevent light leakage and further enhance light extraction efficiency.

An organic light emitting diode display device, according to anembodiment of the present invention, for solving the aforementionedtechnical problem includes a substrate that is divided into an emissivearea and a non-emissive area. Further, the organic light emitting diodedisplay device, according to the embodiment, includes an overcoat layerdisposed on the substrate and having multiple micro lenses in theemissive area and at least one depression in the non-emissive area, andeach micro lens includes a concave portion and a connecting portion.Furthermore, the organic light emitting diode display device, accordingto the embodiment, includes a first electrode disposed on the overcoatlayer and disposed in the entire emissive area and in a part of thenon-emissive area. Moreover, the organic light emitting diode displaydevice, according to the embodiment, includes a bank pattern disposed inthe non-emissive area so as to be superposed on the depression. Inaddition, the organic light emitting diode display device, according tothe embodiment, includes an organic light emitting layer disposed on thesubstrate. Also, the organic light emitting diode display device,according to the embodiment, includes a second electrode disposed on theorganic light emitting layer.

An organic light emitting diode display device, according to anotherembodiment of the present invention, includes a substrate divided intomultiple emissive areas and a non-emissive area that surrounds themultiple emissive areas. Further, the organic light emitting diodedisplay device, according to the other embodiment, includes an overcoatlayer disposed on the substrate and having multiple micro lenses in eachemissive area and at least one depression in the non-emissive area, andeach micro lens includes a concave portion and a connecting portion.Furthermore, the organic light emitting diode display device, accordingto the other embodiment, includes a first electrode disposed on theovercoat layer in the emissive areas. Moreover, the organic lightemitting diode display device, according to the other embodiment,includes an organic light emitting layer disposed on the firstelectrode, the overcoat layer, and the depression. In addition, theorganic light emitting diode display device, according to the otherembodiment, includes a second electrode disposed on the organic lightemitting layer.

In the organic light emitting diode display device, according to thepresent invention, the overcoat layer in the non-emissive area NEA hasthe at least one depression, and the bank pattern is provided so as tobe superposed on the depression, which makes it possible to preventlight emitted from the organic light emitting element from travellingtoward a sub-pixel emitting light having a different color to cause alight leakage phenomenon.

Furthermore, in the organic light emitting diode display device,according to the present invention, the overcoat layer in thenon-emissive area NEA has the at least one depression, and a reflectiveelectrode is disposed along the shape of the depression, which makes itpossible to absorb light travelling toward a sub-pixel emitting lighthaving a different color, among light emitted from an organic lightemitting element, thereby preventing light leakage, or to reflect thelight travelling toward the sub-pixel, thereby enhancing lightextraction efficiency.

In addition, in the organic light emitting diode display device,according to the present invention, the position of the first electrodedisposed on a protruding portion of the overcoat layer is higher thanthat of the organic light emitting element disposed on the connectingportion of the micro lens, which makes it possible to enhance lightextraction efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view of an organic light emitting diode displaydevice to which exemplary embodiments of the present disclosure may beapplied.

FIG. 2 is a plan view of an organic light emitting diode display deviceaccording to a first embodiment of the present disclosure.

FIG. 3 is a sectional view of the organic light emitting diode displaydevice along line A-B of the organic light emitting diode display deviceillustrated in FIG. 2.

FIG. 4 is a plan view illustrating a part of a mask that is used to formmultiple micro lenses and multiple depressions on an overcoat layer ofan exemplary organic light emitting diode display device.

FIG. 5 is a sectional view illustrating the principle by which a lightleakage phenomenon is restricted in the organic light emitting diodedisplay device illustrated in FIG. 2.

FIG. 6 is a sectional view of an organic light emitting diode displaydevice having another type of depression.

FIG. 7 is a sectional view of an organic light emitting diode displaydevice having yet another type of depression.

FIG. 8 is a plan view of an organic light emitting diode display deviceaccording to a second embodiment of the present disclosure.

FIG. 9 is a sectional view along line C-D of the organic light emittingdiode display device illustrated in FIG. 8.

FIG. 10 is a sectional view illustrating the principle by which a lightleakage phenomenon is restricted in the organic light emitting diodedisplay device illustrated in FIG. 8.

FIG. 11 is a plan view of an organic light emitting diode display deviceaccording to a third embodiment of the present disclosure.

FIG. 12 is a sectional view along line E-F of the organic light emittingdiode display device illustrated in FIG. 11.

FIG. 13 is a plan view of an organic light emitting diode display deviceaccording to a fourth embodiment of the present disclosure.

FIG. 14 is a sectional view along line G-H of the organic light emittingdiode display device illustrated in FIG. 13.

FIG. 15 is a plan view of an organic light emitting diode display deviceaccording to a fifth embodiment of the present disclosure.

FIG. 16 is a plan view of an organic light emitting diode display deviceaccording to a sixth embodiment of the present disclosure.

FIG. 17 is a sectional view of one pixel of an organic light emittingdiode display device to which a sub-pixel, according to an embodiment ofthe present disclosure, is applied.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings. The followingembodiments are provided, by way of example, so that the idea of thepresent invention can be sufficiently transferred to those skilled inthe art. Therefore, the present invention is not limited to theembodiments as described below, and may be embodied in other forms.Also, in the drawings, the size, thickness, and the like of a device maybe exaggeratedly represented for the convenience of description.Throughout the specification, the same reference numerals designate thesame elements.

The advantages and features of the present invention and methods ofachieving the same will be apparent by referring to embodiments of thepresent invention as described below in detail in conjunction with theaccompanying drawings. However, the present invention is not limited tothe embodiments set forth below, but may be implemented in variousdifferent forms. The following embodiments are provided only tocompletely disclose the present invention and inform those skilled inthe art of the scope of the present invention, and the present inventionis defined only by the scope of the appended claims. Throughout thespecification, the same or like reference numerals designate the same orlike elements. In the drawings, the dimensions and relative sizes oflayers and regions may be exaggerated for the convenience ofdescription.

When an element or layer is referred to as being “above” or “on” anotherelement, it can be “directly above” or “directly on” the other elementor layer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on” or “directlyabove” another element or layer, there are no intervening elements orlayers present.

Spatially relative terms, such as “below”, “beneath”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the element in use or operation in addition to theorientation depicted in the figures. For example, if the element in thefigures is turned over, elements described as “below” or “beneath” otherelements would then be oriented “above” the other elements. Thus, theexemplary term “below” can encompass both an orientation of above andbelow.

Additionally, in describing the components of the present invention,there may be terms used like first, second, A, B, (a), and (b). Theseare solely for the purpose of differentiating one component from theother but not to imply or suggest the substances, order, sequence, ornumber of the components.

FIG. 1 is a sectional view of an organic light emitting diode displaydevice to which embodiments of the present invention may be applied.Referring to FIG. 1, the organic light emitting diode display device, towhich the embodiments of the present invention are applied, includes athin film transistor Tr and an organic light emitting element ELelectrically connected with the thin film transistor Tr.

Specifically, a gate electrode 101 of the thin film transistor Tr and agate insulation film 102 are disposed on a first substrate 100. Anactive layer 103 is provided on the gate insulation film 102 so as to besuperposed on the gate electrode 101. An etch-stop layer 106 forprotecting a channel area of the active layer 103 is disposed on theactive layer 103.

Further, a source electrode 105 a and a drain electrode 105 b that makecontact with the active layer 103 are disposed on the active layer 103.A protective layer 107 is disposed on the source electrode 105 a and thedrain electrode 105 b. The organic light emitting diode display device,to which the embodiments of the present invention may be applied, is notlimited to that illustrated in FIG. 1, and may further include a bufferlayer disposed between the first substrate 100 and the active layer 103.

Moreover, an overcoat layer 110 a is disposed on the protective layer107. The organic light emitting element EL that includes a firstelectrode 120 a, an organic light emitting layer 130 a, and a secondelectrode 140 a is disposed on the overcoat layer 110 a. Herein, one ofthe first electrode 120 a and the second electrode 140 a may be areflective layer formed of a metal having a high reflectivity.Meanwhile, a surface plasmon component generated at the boundary betweenthe metal and the organic layer and an optical guided-mode constitutedby the organic light emitting layer 130 a inserted between the oppositereflective layers account for about 60% to 70% of emitted light. Since aphenomenon may arise in which light is confined in the organic lightemitting layer 130 a without being emitted, it is necessary to extractlight generated by the organic light emitting layer 130 a from thedisplay device.

To this end, the overcoat layer 110 a of the organic light emittingdiode display device, according to embodiments of the present invention,includes: multiple concave portions 111 a; and multiple connectingportions 112 a, each of which connects the concave portions 111 aadjacent to each other. The multiple concave portions 111 a may have,but are not limited to, a hemispherical or semielliptical shape.

The multiple concave portions 111 a and the connecting portions 112 aconnecting the adjacent concave portions 111 a may be disposed tocorrespond to the emissive area of each sub-pixel. Herein, the emissivearea refers to an area where the organic light emitting layer 130 aemits light by means of the first electrode 120 a and the secondelectrode 140 a.

Since the multiple concave portions 111 a and the connecting portions112 a connecting the adjacent concave portions 111 a are disposed tocorrespond to the emissive area of each sub-pixel, light emitted fromthe organic light emitting element EL may be further extracted from thedisplay device.

The first electrode 120 a of the organic light emitting element EL,which is connected with the drain electrode 105 b of the thin filmtransistor Tr, is disposed on the overcoat layer 110 a. Furthermore,although not illustrated in the drawing, a reflective layer may beadditionally disposed below the first electrode 120 a.

Further, a bank pattern 150 a is disposed on the overcoat layer 110 a toexpose a part of the upper surface of the first electrode 120 a. Theorganic light emitting layer 130 a is disposed on the upper surface ofthe first electrode 120 a that is exposed by the bank pattern 150 a andon the bank pattern 150 a.

Herein, the organic light emitting layer 130 a may be disposed only onthe upper surface of the first electrode 120 a that is exposed by thebank pattern 150 a, or may be disposed both on the first electrode 120 aand on the bank pattern 150 a. Further, the second electrode 140 a ofthe organic light emitting element EL is provided so as to be superposedon the organic light emitting layer 130 a and the bank pattern 150 a.

Moreover, an encapsulation layer 160 is disposed on the second electrode140 a to protect the organic light emitting element EL from moisture andoxygen. While the encapsulation layer 160 is illustrated in FIG. 1 ashaving a single layer, the embodiments of the present invention is notlimited thereto, and the encapsulation layer 160 may have multiplelayers. A second substrate 170 may be disposed on the encapsulationlayer 160.

In addition, although not illustrated in the drawing, a polarizing platemay be disposed on the upper surface of the second substrate 170. Thepolarizing plate may be a polarizing plate having a polarization axisdirected in a predetermined direction, and may only transmit lighthaving the same optical axis as the polarization axis among lightincident to the upper surface of the second substrate 170. While thepolarizing plate has been described as being disposed on the uppersurface of the second substrate 170, the present invention is notlimited thereto, and the polarizing plate may be disposed on the rearsurface of the first substrate 100.

The polarizing plate may be constituted by a single layer or multiplelayers. While the polarizing plate has been described as having apolarization axis directed in a predetermined direction, the embodimentsof the present invention are not limited thereto, and the polarizingplate may further include a phase retardation film.

Furthermore, although the description of FIG. 1 is focused on thetop-emission type organic light emitting diode display device, theembodiments of the present invention may also be applied to a bottom- ordual-emission type organic light emitting diode display device accordingto necessity.

In a case where the embodiments of the present invention are applied toa bottom-emission type organic light emitting diode display device, acolor filter layer may be disposed on the protective layer 107. In thiscase, the color filter layer may be disposed on each of multiplesub-pixels, or may be disposed only on some of the multiple pixels.

Meanwhile, the color filter layer may be disposed to correspond to theemissive area of each sub-pixel. Herein, the emissive area refers to anarea where the organic light emitting layer 130 a emits light by meansof the first electrode 120 a and the second electrode 140 a, and whenthe color filter layer is formed to correspond to the emissive area,that means that the color filter is disposed to prevent blurring and aghost image problem caused by the mixture of light emitted from adjacentemissive areas.

In order to enhance the light extraction efficiency of the organic lightemitting diode display device mentioned above, the overcoat layer 110 amay be employed that has micro lenses formed thereon, which areconstituted by the concave portions 111 a and the connecting portions112 a connecting the adjacent concave portions 111 a.

In this case, among light incident to the interface between the microlenses and the first electrode 120 a of the organic light emittingelement, light having an incidence angle smaller than or equal to atotal-reflection critical angle is reflected by the reflective layer andextracted from the second substrate 170 as it is. In contrast, lighthaving an incidence angle larger than or equal to the total-reflectioncritical angle collides with the micro lenses to change its opticalpath, finally escaping from the second substrate 170 with a light travelangle smaller than the total-reflection critical angle without beingconfined in the organic light emitting element EL.

Meanwhile, each pixel of the present invention includes one or moresub-pixels. For example, one pixel may include two to four sub-pixels.

The sub-pixel refers to a unit by which a particular type of colorfilter layer is formed, or a unit by which the organic light emittingelement may emit light having a particular color without the formationof a color filter layer. While the color defined by the sub-pixel mayinclude red (R), green (G), and blue (B) and may selectively includewhite (W), the present invention is not limited thereto.

An electrode connected to a thin film transistor that controls lightemission of each sub-pixel area of a display panel is referred to as afirst electrode, and an electrode disposed on the front of the displaypanel, or disposed to include two or more pixel areas, is referred to asa second electrode. When the first electrode is an anode electrode, thesecond electrode is a cathode electrode, and vice versa. Although thefollowing description is made under the assumption that the firstelectrode is exemplified by an anode electrode and the second electrodeis exemplified by a cathode electrode, the present invention is notlimited thereto.

Furthermore, a color filter layer having one color may be disposed inthe sub-pixel area mentioned above, but the present invention is notlimited thereto. In addition, a light-scattering layer may be disposedin each sub-pixel area in order to enhance the light extractionefficiency of the organic light emitting layer. The light-scatteringlayer mentioned above may be referred to as a micro lens array, a microlens, a nano pattern, a diffusion pattern, a silica bead, or anout-coupling structure.

While the following description is made assuming that thelight-scattering layer is exemplified by a micro lens, the embodimentsaccording to the present invention are not limited thereto, and varioustypes of structures may be coupled to scatter light.

Hereinafter, embodiments of an organic light emitting diode displaydevice of the present invention, which may be applied to the organiclight emitting diode display device mentioned above, will be described.

FIG. 2 is a plan view of an organic light emitting diode display deviceaccording to a first embodiment of the present invention. FIG. 2illustrates an emissive area EA and a part of a non-emissive areaadjacent to the emissive area EA in one sub-pixel. Herein, the emissivearea EA may be an emissive area EA that emits light having one color ofred (R), green (G), blue (B), and white (W), but is not limited thereto.

Meanwhile, in the organic light emitting diode display device, accordingto the first embodiment of the present invention, one pixel may includetwo to four sub-pixels, and elements to be described with reference toFIG. 2 may be applied to at least one of the sub-pixels that constituteone pixel.

Multiple micro lenses are arranged in the emissive area EA. The multiplemicro lenses may enhance external light extraction efficiency. Each ofthe multiple micro lenses may include a concave portion 111 of anovercoat layer 110 and a connecting portion 112 that connects theconcave portion 111 and another concave portion 111 adjacent thereto.Further, an organic light emitting element may be disposed on theovercoat layer 110 having the multiple micro lenses formed thereon.

While the micro lenses are illustrated as having a hexagonal shape onthe plane of FIG. 2, the shape of the micro lenses, according to thefirst embodiment of the present invention, is not limited thereto, andthe micro lenses may have a circular or elliptical shape.

A first electrode 120 of the organic light emitting element and a bankpattern 150 superposed on the first electrode 120 are provided in a partof the non-emissive area adjacent to the emissive area EA. Herein, thebank pattern 150 may be provided so as to be superposed on depressionsformed in the overcoat layer 110. This configuration will be describedbelow in detail with reference to FIG. 3.

While the depressions formed in the overcoat layer 110 are illustratedin FIG. 3 as surrounding the emissive area EA on the plane, the organiclight emitting diode display device, according to the first embodimentof the present invention, is not limited thereto. For example, thedepressions 117 may be disposed on at least one of the upper and lowersides of the emissive area EA on the plane, or may be disposed on atleast one of the left and right sides of the emissive area EA on theplane.

Particularly, in the case where the depressions are disposed on at leastone of the upper and lower sides of the emissive area EA, substanceshaving low molecular weights may easily escape from a less cured area ofthe overcoat layer 110 while the overcoat layer 110 is being cured.Specifically, when a semi-cured region is generated in the overcoatlayer 110, out-gassing may be induced by substances having low molecularweights, which may cause a defect in the panel. However, since thedepressions of the overcoat layer 110 are disposed on at least one sideof the emissive area EA in this embodiment, substances having lowmolecular weights may escape from the overcoat layer 110, therebypreventing a defect in the panel.

FIG. 3 is a sectional view of the organic light emitting diode displaydevice, according to the first embodiment of the present invention,which is taken along line A-B of FIG. 2. Referring to FIG. 3, theorganic light emitting diode display device, according to the firstembodiment of the present invention, includes a first substrate 100 thatis divided into an emissive area EA and a non-emissive area NEA.

The emissive area EA includes multiple micro lenses disposed on theovercoat layer 110, and each of the micro lenses is constituted by aconcave portion 111 and a connecting portion 112 that connects theconcave portion 111 and another concave portion. Meanwhile, in a casewhere the organic light emitting diode display device, according to thisembodiment, includes a color filter layer disposed below the overcoatlayer 110, the color filter layer may be exposed by the multiple microlenses, or may not be exposed. Herein, when the color filter layer isexposed by the multiple micro lenses, the surface of the color filterlayer may have the shape of the multiple micro lenses.

Specifically, the areas of the color filter layer that correspond to theconcave portions of the multiple micro lenses provided on the overcoatlayer 110 may be exposed. Further, the color filter layer may havemultiple concave portions in the areas thereof that correspond to themultiple concave portions of the overcoat layer 110, and may includemultiple convex portions together with the concave portions in somecases.

Accordingly, a light extraction effect by means of the micro lenses maynot be affected even though the color filter layer is exposed by themultiple micro lenses. Specifically, although the organic light emittingelement EL may emit the weakest light from the areas thereof thatcorrespond to the concave portions of the multiple micro lenses of theovercoat layer 110, the exposure of the color filter layer may not havea great effect on the light extraction efficiency by means of the microlenses since the areas where the color filter layer is exposedcorrespond to the concave portions of the multiple micro lenses of theovercoat layer 110.

The organic light emitting element EL, which includes the firstelectrode 120, an organic light emitting layer 130, and a secondelectrode 140, is disposed on the multiple micro lenses.

Herein, a concave pattern may appear on the surface of the organic lightemitting element EL on account of the morphology of the multiple microlenses, but the present invention is not limited thereto. While themultiple micro lenses are illustrated in FIG. 2 as including themultiple concave portions, the embodiments of the present invention arenot limited thereto, and the multiple micro lenses may include multipleconvex portions.

Further, at least one step 115 may be formed on the overcoat layer 110in the non-emissive area NEA or in the emissive area EA adjacent to thenon-emissive area NEA. This may help to prevent a short circuit of thefirst electrode 120 disposed on the overcoat layer 110.

Specifically, the slope of the overcoat layer 110 at the boundarybetween the emissive area EA and the non-emissive area NEA may varysharply on account of the multiple micro lenses disposed on the overcoatlayer 110 in the emissive area EA, which may cause a short circuit ofthe first electrode 120.

In this case, since the overcoat layer 110 includes the at least onestep 115 at the boundary between the emissive area EA and thenon-emissive area NEA, it is possible to reduce the slope of theovercoat layer 110 caused by the micro lenses to prevent the shortcircuit of the first electrode 120 disposed on the overcoat layer 110.

Furthermore, the non-emissive area NEA includes at least one depression117 provided on the overcoat layer 110. Specifically, the non-emissivearea NEA may include multiple depressions 117 on the overcoat layer 110.

Herein, the height H1 of the depressions 117 may be less than the heightH2 of the overcoat layer 110 in the non-emissive area NEA. Meanwhile, ina case where the organic light emitting diode display device, accordingto this embodiment, includes a color filter layer disposed below theovercoat layer 110, the color filter layer may be exposed by thedepressions 117, or may not be exposed.

Namely, the overcoat layer 110 of the organic light emitting diodedisplay device, according to the first embodiment of the presentinvention, may have the multiple micro lenses formed in the emissivelayer EA and the multiple depressions 117 formed in the non-emissivearea NEA. The overcoat layer 110 may be obtained through patterningusing a mask.

A mask necessary for forming the overcoat layer 110 having theaforementioned structure will be described below with reference to FIG.4. FIG. 4 illustrates a part of a mask that is used to form multiplemicro lenses and multiple depressions on an overcoat layer.

Referring to FIG. 4, the overcoat layer of the organic light emittingdiode display device, according to the first embodiment of the presentinvention, may include multiple micro lenses and multiple depressionsformed through an exposure process using the mask 600. The mask 600 mayhave a plurality of first patterns 601 for forming the multiple microlenses and a plurality of second patterns 602 for forming the multipledepressions.

When the overcoat layer is subjected to exposing, the mask 600 isdisposed opposite to the substrate on which the overcoat layer isdisposed. In this case, the plurality of first patterns 601 of the maskmay be arranged to correspond to the emissive area of the substrate, andthe plurality of second patterns 602 may be arranged to correspond tothe non-emissive area of the substrate. Meanwhile, the first patterns601 and the second patterns 602 may transmit or block light according tothe material of the overcoat layer.

The first electrode 120 of the organic light emitting element ELdisposed in the emissive area EA may extend so as to be disposed on thedepressions 117. In this case, the first electrode 120 may be disposedto fill only a part of each depression 117. Further, the bank pattern150 may be disposed to completely fill the remaining part of thedepression 117.

In this case, the bank pattern 150 may define the emissive area EA andthe non-emissive area NEA. Further, the organic light emitting layer 130and the second electrode 140 of the organic light emitting element ELmay extend from the emissive area EA so as to be disposed on the bankpattern 150. While the organic light emitting layer 130 is illustratedin FIG. 5 as being disposed on the bank pattern 150, the firstembodiment of the present invention is not limited thereto, and theorganic light emitting layer 130 may be disposed only on the firstelectrode 120 that is provided in the emissive area EA.

The bank pattern 150 that fills the at least one depression 117 providedin the non-emissive area NEA may be formed of an opaque organicmaterial. Accordingly, the bank pattern 150 may prevent light emittedfrom the organic light emitting element EL from reaching a differentadjacent sub-pixel and being extracted as a light leakage component.

Such a principle will be described below in detail with reference toFIG. 5. FIG. 5 is a view illustrating the principle by which a lightextraction phenomenon and a light leakage phenomenon are restricted inthe organic light emitting diode display device according to the firstembodiment of the present invention.

Referring to FIG. 5, light 1000 emitted from the organic light emittingelement EL is output in a 360 degree direction, that is,omnidirectionally. Herein, a part of the light 1000 emitted from theorganic light emitting element EL is extracted from the first substrate100 through the micro lenses.

Specifically, in a case where the organic light emitting diode displaydevice, according to this embodiment, is a bottom-emission type organiclight emitting diode display device, the refractive indices of the firstelectrode 120 and the organic light emitting layer 130 of the organiclight emitting element EL may be higher than those of the firstsubstrate 100 and the overcoat layer 110. For example, the firstsubstrate 100 and the overcoat layer 110 may have a refractive index ofabout 1.5, and the first electrode 120 and the organic light emittinglayer 130 of the organic light emitting element EL may have a refractiveindex of 1.7 to 2.0.

Herein, since the organic light emitting layer 130 has almost the samerefractive index as that of the first electrode 120, the optical path ofthe light 1000 generated from the organic light emitting layer 130 isnot varied at the interface between the organic light emitting layer 130and the first electrode 120. Meanwhile, due to a difference in therefractive index between the first electrode 120 and the overcoat layer110, the light 1000 having passed through the first electrode 120 may beinput with an incidence angle smaller than a total-reflection criticalangle, or with an incidence angle larger or equal to thetotal-reflection critical angle, through the interface between the firstelectrode 120 and the overcoat layer 110.

In this case, the light that is input with an incidence angle smallerthan the total-reflection critical angle through the interface betweenthe first electrode 120 and the overcoat layer 110 may be extracted fromthe first substrate 100. The light travelling toward the secondsubstrate (not illustrated) of the organic light emitting element EL isreflected by the second electrode 140 to travel toward the firstsubstrate 100 and is extracted from the first substrate 100 by means ofthe micro lenses. This may help to enhance the light extractionefficiency in the emissive area EA.

Furthermore, in a case where the organic light emitting diode displaydevice, according to this embodiment, is a top-emission type organiclight emitting diode display device, a part of light emitted from theorganic light emitting element EL is output toward the second substrate(not illustrated). In addition, a part of the light emitted from theorganic light emitting element EL is reflected by the first electrode120 and extracted from the second substrate (not illustrated).

Moreover, light directed toward an adjacent sub-pixel among the light1000 generated from the organic light emitting element EL may travelalong the overcoat layer 110 by means of an additional inclined surfacethat is generated by the micro lenses formed at the edge of the emissivearea EA, and may reach the adjacent sub-pixel emitting light having adifferent color to cause a light leakage phenomenon. Particularly, in acase where the first electrode 120 is not a reflective electrode, thelight leakage phenomenon may be a serious problem.

Meanwhile, in this embodiment, the bank pattern 150 is provided so as tobe superposed on the at least one depression 117 formed in the overcoatlayer 110 in the non-emissive area NEA. Accordingly, the bank pattern150 may prevent light directed toward an adjacent sub-pixel, among thelight 1000 generated from the organic light emitting element EL, fromtravelling along the overcoat layer 110 and reaching the sub-pixelemitting light having a different color.

In this case, the bank pattern 150 may be formed of an opaque organicmaterial to absorb the light travelling along the overcoat layer 110.Accordingly, the bank pattern 150 may prevent light from travelling to adifferent adjacent sub-pixel. Furthermore, since the bank pattern 150 isdisposed to completely fill the depressions 117, the bank pattern 150may absorb all the light that reaches the depressions 117 to prevent thelight from travelling to a different adjacent sub-pixel. This may helpto restrict light leakage between different sub-pixels.

The depression according to the present invention may be formed asillustrated in FIG. 6. FIG. 6 is a sectional view of an organic lightemitting diode display device having another type of depression.

The organic light emitting diode display device of FIG. 6 may includethe same elements as those of the organic light emitting diode displaydevice in the aforementioned embodiment. Repetitive descriptionsidentical to ones given in the aforementioned embodiment will beomitted. Also, identical elements are provided with identical referencenumerals.

Referring to FIG. 6, the organic light emitting diode display device,according to the present invention, includes one depression 217 providedon an overcoat layer 210 in the non-emissive area NEA of one sub-pixel.In this case, a first electrode 120 of an organic light emitting elementEL is disposed to fill a part of the depression 217, and a bank pattern250 is disposed on the first electrode 120 to fill the remaining part ofthe depression 217.

Since the bank pattern 250 is disposed deep in the overcoat layer 210through the depression 217, the bank pattern 250 may absorb lightdirected toward an adjacent sub-pixel among light emitted from theorganic light emitting element EL to prevent the light from travellingto the different sub-pixel.

Also, the depression according to the present invention may be formed asillustrated in FIG. 7. FIG. 7 is a sectional view of an organic lightemitting diode display device having yet another type of depression.

The organic light emitting diode display device of FIG. 7 may includethe same elements as those of the organic light emitting diode displaydevices in the aforementioned embodiments. Repetitive descriptionsidentical to ones given in the aforementioned embodiments will beomitted. Also, identical elements are provided with identical referencenumerals.

Referring to FIG. 7, the organic light emitting diode display device,according to the present invention, includes multiple depressions 317provided on an overcoat layer 310 in the non-emissive area NEA of onesub-pixel. In this case, the depressions 317 may be disposed to expose afirst substrate 100.

Further, a bank pattern 350 may be disposed to completely fill thedepressions 317. In this case, the bank pattern 350 may be disposed tooverlap a first electrode 120. For example, the bank pattern 350 may bedisposed to overlap the first electrode 120 in the non-emissive area NEAother than the depressions 317. That is, the bank pattern 350 may notoverlap the first electrode 120 within the depressions 317, but thepresent invention is not limited thereto.

Since the depressions 317 are located to expose the first substrate 100,and the bank pattern 350 is provided to completely fill the entiredepressions 317, the bank pattern 350 may effectively absorb lighttravelling toward an adjacent sub-pixel among light emitted from theorganic light emitting element EL. Specifically, the bank pattern 350has a vertical length corresponding to the vertical length H2 of theovercoat layer 310 so that the bank pattern 350 may absorb all the lighttravelling along the overcoat layer 310. Accordingly, the bank pattern150 may prevent the light from travelling to a different adjacentsub-pixel.

Next, an organic light emitting diode display device, according to asecond embodiment of the present invention, will be described below withreference to FIGS. 8 to 10. The organic light emitting diode displaydevice, according to the second embodiment of the present invention, mayinclude the same elements as those of the organic light emitting diodedisplay devices in the aforementioned embodiments. Repetitivedescriptions identical to ones given in the aforementioned embodimentswill be omitted. Also, identical elements are provided with identicalreference numerals.

FIG. 8 is a plan view of the organic light emitting diode display deviceaccording to the second embodiment of the present invention. FIG. 8illustrates an emissive area (EA) and a part of a non-emissive areaadjacent to the emissive area (EA) in one sub-pixel.

Multiple micro lenses are arranged in the emissive area (EA). Each ofthe multiple micro lenses may include a concave portion 411 of anovercoat layer 410 and a connecting portion 412 that connects theconcave portion 411 and another concave portion 411 adjacent thereto.Further, an organic light emitting element may be disposed on theovercoat layer 410 having the multiple micro lenses formed thereon.

A first electrode of the organic light emitting element and a bankpattern superposed on the first electrode are provided in a part of thenon-emissive area adjacent to the emissive area EA. Herein, the bankpattern may be provided so as to be superposed on depressions formed inthe overcoat layer 410 in the non-emissive area.

In this case, the bank pattern may be disposed to fill only a part ofeach depression. Further, an organic light emitting layer and a secondelectrode 240 of the organic light emitting element may be disposed inthe sub-pixel that includes the bank pattern. This configuration will bedescribed below in detail with reference to FIG. 9.

FIG. 9 is a sectional view of the organic light emitting diode displaydevice, according to the second embodiment of the present invention,which is taken along line C-D of FIG. 8. Referring to FIG. 9, theorganic light emitting diode display device, according to the secondembodiment of the present invention, includes a first substrate 100 thatis divided into an emissive area EA and a non-emissive area NEA.

The emissive area EA includes multiple micro lenses disposed on theovercoat layer 410, and each of the micro lenses is constituted by aconcave portion 411 and a connecting portion 412 that connects theconcave portion 411 and another concave portion. The organic lightemitting element EL that includes the first electrode 320, the organiclight emitting layer 230, and the second electrode 240 is disposed onthe multiple micro lenses.

Further, at least one step 415 may be formed on the overcoat layer 410in the non-emissive area NEA or in the emissive area EA adjacent to thenon-emissive area NEA. Furthermore, the non-emissive area NEA includesat least one depression 417 provided on the overcoat layer 410.

While multiple depressions 417 are illustrated in FIG. 9 as beingdisposed on the overcoat layer 410 in the non-emissive area NEA, thesecond embodiment of the present invention is not limited thereto, andone depression 417 may be disposed on the overcoat layer 410 in thenon-emissive area NEA.

The multiple micro lenses are arranged in the emissive area EA, and thefirst electrode 320 of the organic light emitting element EL is disposedon the overcoat layer 410 having the multiple depressions 417 formed inthe non-emissive area NEA. In this case, the first electrode 320 may beformed to have a morphology that corresponds to the surface shapes ofthe multiple micro lenses and the multiple depressions 417.

Furthermore, the first electrode 320 may be disposed to fill a part ofeach depression 417. The bank pattern 450 may be disposed to fill a partof the depression 417 in which the first electrode 320 is disposed.

The bank pattern 450 may be formed of a transparent organic material oran opaque organic material. Herein, the bank pattern 450 may define theemissive area EA and the non-emissive area NEA of the sub-pixel and mayprevent light leakage between sub-pixels.

The organic light emitting layer 230 and the second electrode 240 aredisposed on the first substrate 100 on which the bank pattern 450 isdisposed. The second electrode 240 may be a reflective electrode formedof a high-refractive material. Herein, the organic light emitting layer230 and the second electrode 240 may also have a morphology thatcorresponds to the multiple micro lenses and the multiple depressions417.

Meanwhile, the bank pattern 450 and the second electrode 240 of theorganic light emitting element EL may prevent light travelling toward anadjacent sub-pixel, among light emitted from the organic light emittingelement EL, from travelling to a different adjacent sub-pixel, therebypreventing light leakage. Such a principle will be described below withreference to FIG. 10.

FIG. 10 is a view illustrating the principle by which a light leakagephenomenon is restricted in the organic light emitting diode displaydevice according to the second embodiment of the present invention.Referring to FIG. 10, in the organic light emitting diode displaydevice, according to the second embodiment of the present invention,light emitted from the organic light emitting element EL is refracted atthe interface between the overcoat layer 410 and the first electrode 320in the non-emissive area NEA due to a difference in the refractive indextherebetween and is input to the first electrode 320. The light input tothe first electrode 320 may be absorbed into, or transmitted through,the bank pattern 450 disposed on the first electrode 320.

The light having passed through the bank pattern 450 reaches the secondelectrode 240 via the organic light emitting layer 230 disposed on thebank pattern 450. Herein, the first electrode 320, the bank pattern 450,and the organic light emitting layer 230 may have similar refractiveindices so that the light may travel without a change in its opticalpath.

Meanwhile, the light that reaches the second electrode 240 formed of areflective material may be absorbed or reflected. Herein, in a casewhere the light is absorbed by the second electrode 240, it is possibleto prevent light directed toward an adjacent sub-pixel, among the light1100 generated from the organic light emitting element EL, fromtravelling along the overcoat layer 410 to reach the sub-pixel emittinglight having a different color.

Furthermore, in a case where the light is reflected by the secondelectrode 240, the light may be extracted from the first substrate 100via the micro lenses arranged in the emissive area EA. As a result, thelight extraction efficiency in the emissive area EA may be enhanced.

Next, a third embodiment of the present invention will be describedbelow with reference to FIG. 11. An organic light emitting diode displaydevice, according to this embodiment, may include the same elements asthose of the organic light emitting diode display devices in theaforementioned embodiments. Repetitive descriptions identical to onesgiven in the aforementioned embodiments will be omitted. Also, identicalelements are provided with identical reference numerals.

FIG. 11 is a plan view of the organic light emitting diode displaydevice according to the third embodiment of the present invention.Referring to FIG. 11, one pixel P may include four sub-pixels SP1, SP2,SP3, and SP4 in the organic light emitting diode display deviceaccording to the third embodiment of the present invention. In thiscase, the sub-pixels may emit light having different colors,respectively.

An emissive area and a non-emissive area may be distinguished from eachother by a bank pattern 550 in the organic light emitting diode displaydevice according to the third embodiment. Specifically, the area wherethe bank pattern 550 is disposed may be defined as the non-emissivearea, and the area where the bank pattern 550 is not disposed may bedefined as the emissive area.

An organic light emitting element that includes a first electrode 121,an organic light emitting layer (not illustrated), and a secondelectrode (not illustrated) may be disposed in the emissive area, andthe organic light emitting element may extend to a part of thenon-emissive area.

Specifically, the first electrode 121, which is one of the elements ofthe organic light emitting element, may be disposed in the emissivearea, and may extend to a part of the non-emissive area adjacent to theemissive area. Further, the organic light emitting layer (notillustrated) and the second electrode (not illustrated) may be disposedin the active area of the organic light emitting diode display panel,but the present invention is not limited thereto.

This configuration will be described below in detail with reference toFIG. 12. FIG. 12 is a sectional view taken along line E-F of FIG. 11.Referring to FIG. 12, the organic light emitting element EL thatincludes the first electrode 121, the organic light emitting layer 130,and the second electrode 140 is disposed in the emissive area EA in theorganic light emitting diode display device according to the thirdembodiment.

Herein, the first electrode 121 may extend to a part of the non-emissivearea NEA adjacent to the emissive area EA. Specifically, an overcoatlayer 110 has at least one step 115 in the non-emissive area NEA or inthe emissive area EA adjacent to the non-emissive area NEA, and at leastone depression 117 is disposed adjacent to the at least one step 115.Furthermore, the depression 117 located adjacent to the step 115 isconnected to a protruding portion 217. In other words, the overcoatlayer 110 includes the depression 117 located adjacent to the step 115and at least one protruding portion 217 provided between the depression117 and the step 115.

The first electrode 121 of the organic light emitting element EL may bedisposed on the step 115 of the overcoat layer 110 in the non-emissivearea NEA, and may further extend to a part of the protruding portion 217of the overcoat layer 110, which is located behind the start point ofthe depression 117 disposed adjacent to the step 115.

In this case, the first electrode 121 may be a reflective electrode.Accordingly, a part of light emitted from the organic light emittinglayer 130 is output toward a second substrate (not illustrated), and apart of the light is output toward a first substrate 100. However, thelight output toward the first substrate 100 may be reflected by thefirst electrode 121, which is a reflective electrode, to travel towardthe second substrate (not illustrated) and may be extracted from thesecond substrate.

Furthermore, the light emitted from the organic light emitting layer 130may be output toward the non-emissive area NEA having no micro lenses.In this case, the light output toward the non-emissive area NEA may bereflected by the first electrode 121, which is a reflective electrode,and may be extracted toward the second substrate (not illustrated), asillustrated in FIG. 12.

Specifically, since the first electrode 121 extends to a part of theprotruding portion 217 of the overcoat layer 110 in the non-emissivearea NEA, which is located behind the start point of the depression 117disposed adjacent to the step 115, the light output toward thenon-emissive area NEA having no micro lenses may be extracted toward thesecond substrate (not illustrated) with an optical path changed by thefirst electrode 121.

While the first electrode 121 is illustrated in FIG. 12 as extending toa part of the protruding portion 217 of the overcoat layer 110 in thenon-emissive area NEA, which is located behind the start point of thedepression 117 disposed adjacent to the step 115, the first electrode121 may further extend to a part of the depression 117.

In addition, the height H3 from concave portions 111 to connectionportions 112 of micro lenses, according to this embodiment, may be lessthan the height H4 from the concave portions 111 of the micro lenses tothe protruding portion 217 of the overcoat layer 110. Due to this, theposition of the first electrode 121 disposed on the protruding portion217 of the overcoat layer 110 may be higher than that of the firstelectrode 121 disposed on the connecting portions 112 of the microlenses.

Although the micro lenses of this embodiment may have a sectional shapeillustrated in FIG. 13, this embodiment is not limited thereto, and themicro lenses may have a sectional shape similar to those of the microlenses in the aforementioned embodiments.

Specifically, the position of the first electrode 121 disposed on theprotruding portion 217 of the overcoat layer 110 may be higher than thatof the organic light emitting element EL disposed on the connectingportions 212 of the micro lenses provided in the emissive area EA. Thismay help to effectively extract, from the display panel, light outputtoward the non-emissive area NEA among the light emitted from theorganic light emitting element EL.

For example, assuming that the first electrode 121 extends only to thestep 115 of the non-emissive area NEA, light extraction efficiency maybe lower than that of the display device according to this embodimentsince light output toward the protruding portion 127 of the overcoatlayer 110 among the light emitted from the organic light emittingelement EL is reflected by the first electrode 121 so that it cannot beextracted from the display panel.

Namely, since the height H3 from the concave portions 111 to theconnecting portions 112 of the micro lenses is less than the height H4from the concave portions 111 of the micro lenses to the protrudingportion 217 of the overcoat layer 110, the light extraction efficiencyof the organic light emitting diode display device may be enhanced. Inother words, since the position of the first electrode 121 disposed onthe protruding portion 217 of the overcoat layer 110 may be higher thanthat of the organic light emitting element EL disposed on the connectingportions 112 of the micro lenses provided in the emissive area EA, thelight extraction efficiency may be enhanced.

While the first electrode 121 is illustrated as a reflective electrodein FIGS. 11 and 12, the first electrode 121 may be formed of atransparent conductive material, and a reflective layer may beadditionally provided between the first electrode 121 and the overcoatlayer 110 without being limited thereto. In this case, the reflectivelayer may be disposed in the same form as that of the first electrode121 to enhance the light extraction efficiency of the organic lightemitting diode display device.

Next, an organic light emitting diode display device, according to afourth embodiment of the present invention, will be described below withreference to FIGS. 13 and 14. The organic light emitting diode displaydevice, according to the fourth embodiment of the present invention, mayinclude the same elements as those of the organic light emitting diodedisplay devices in the aforementioned embodiments. Repetitivedescriptions identical to ones given in the aforementioned embodimentswill be omitted. Also, identical elements are provided with identicalreference numerals.

FIG. 13 is a plan view of the organic light emitting diode displaydevice according to the fourth embodiment of the present invention.Referring to FIG. 13, one pixel P may include four sub-pixels SP1, SP2,SP3, and SP4 in the organic light emitting diode display deviceaccording to the fourth embodiment of the present invention. In theorganic light emitting diode display device, according to the fourthembodiment, emissive areas EA and a non-emissive area NEA may bedistinguished from each other by bank patterns 650 and a first electrodeof an organic light emitting element.

Specifically, the organic light emitting element, which includes thefirst electrode, an organic light emitting layer, and a secondelectrode, may be disposed in the emissive areas EA. The organic lightemitting layer and the second electrode of the organic light emittingelement may extend to the non-emissive area NEA from the emissive areasEA. Further, the non-emissive area NEA may include regions where thebank patterns 650 are disposed and a region where the bank patterns 650are not disposed.

Meanwhile, since the first electrode of the organic light emittingelement is not disposed in the region of the non-emissive area NEA wherethe bank patterns 650 are not disposed, the organic light emittingelement may not emit light. An overcoat layer may also not be disposedin the region of the non-emissive area NEA where the bank patterns 650are not disposed. In other words, the overcoat layer may havedepressions 517 or recesses in a part of the non-emissive area NEA.Further, the bank patterns 650 may not be disposed in the areas thatcorrespond to the depressions 517 or recesses of the overcoat layer.

This configuration will be described below in detail with reference toFIG. 14. FIG. 14 is a sectional view taken along line G-H of FIG. 13.Referring to FIG. 14, the organic light emitting diode display device,according to the fourth embodiment, may include a color filter layer 670disposed on a substrate 100 that is divided into emissive areas EA and anon-emissive area NEA. While a sub-pixel having the color filter layer670 disposed therein and a sub-pixel having no color filter layer 670are both illustrated in FIG. 14, the organic light emitting diodedisplay device, according to this embodiment, includes a configurationin which all sub-pixels have no color filter layer 670 and aconfiguration in which all sub-pixels have the color filter layers 670disposed therein.

An overcoat layer 610 is disposed on the color filter layer 670 and thesubstrate 100. The overcoat layer 610 may be provided with multiplemicro lenses in an area thereof that corresponds to each emissive areaEA, and each micro lens includes multiple concave portions and multipleconvex portions. Further, the overcoat layer 610 may include one or moredepressions 517 in the area corresponding to the non-emissive area NEA.

Moreover, the organic light emitting element EL, which includes thefirst electrode 320, the organic light emitting layer 330, and thesecond electrode 340, is disposed on the overcoat layer 610 tocorrespond to the emissive areas EA. Herein, the first electrode 320 maybe formed of a transparent conductive material, and the second electrode340 may be formed of a reflective material. Since the first electrode320 is formed of a transparent conductive material and the secondelectrode 340 is formed of a reflective material, the organic lightemitting diode display device, according to the fourth embodiment, mayimplement a bottom-emission type organic light emitting diode displaydevice.

In addition, the bank patterns 650 may be only disposed on the overcoatlayer 610 corresponding to the non-emissive area NEA. In other words,the bank patterns 650 may not be disposed in the regions of thenon-emissive area NEA that correspond to the depressions 517 of theovercoat layer 610. In this case, the bank patterns 650 may be disposedsuch that the side surfaces of the overcoat layer 610 are exposed in theareas corresponding to the depressions 517 of the overcoat layer 610.

The bank patterns 650 may be formed of a transparent organic material oran opaque organic material. Namely, a material capable of distinguishingbetween the emissive areas EA and the non-emissive area NEA will sufficefor the bank patterns 650 of the organic light emitting diode displaydevice according to the fourth embodiment.

Furthermore, the organic light emitting layer 330 and the secondelectrode 340 of the organic light emitting element EL may extend to thenon-emissive area NEA. In this case, the organic light emitting layer330 and the second electrode 340 may be disposed on the bank patterns650 in the non-emissive area NEA adjacent to the emissive areas EA.

The organic light emitting layer 330 and the second electrode 340 may bedisposed on the depressions 517 of the overcoat layer 610. Namely, theorganic light emitting layer 330 and the second electrode 340 may alsobe disposed on the side surfaces of the overcoat layer 610 that areexposed by means of the bank patterns 650 in the areas corresponding tothe depressions 517 of the overcoat layer 610.

In other words, since the overcoat layer 610 has the one or moredepressions 517 in the non-emissive area NEA, one or more surfacesthereof may be inclined surfaces 611. Accordingly, the organic lightemitting layer 330 and the second electrode 340 may have inclinedsurfaces corresponding to the inclined surfaces 611 of the overcoatlayer 610 in the non-emissive area NEA.

Namely, the second electrode 340, which is a reflective electrode, mayhave concave portions 341 and a convex portion 642 on account of thedepressions 517 provided in the overcoat layer 610. In this case, theconcave portions 341 of the second electrode 340 may be provided tocorrespond to the depressions 517 of the overcoat layer 610.

When the overcoat layer 610 has multiple depressions 517 in thenon-emissive area NEA, the second electrode 340 may have multipleconcave portions 341 and multiple convex portions 642 in thenon-emissive area NEA. That is, the second electrode 340, which is areflective electrode, may have an out-coupling structure in thenon-emissive area NEA.

While a part of light emitted from the organic light emitting element ELdisposed in the emissive area EA may be extracted from the substrate100, a part of the light that is not extracted from the substrate 100 isconfined within the display device due to total reflection caused by adifference in refractivity between the substrate 100 and air.

Specifically, among the light emitted from the organic light emittingelement EL disposed in the emissive area EA, light incident to thesubstrate 100 with an incidence angle larger than or equal to atotal-reflection critical angle (for example, 60□) is confined withinthe substrate 100 without being extracted from the substrate 100 due tototal reflection at the boundary between the substrate 100 and air,which is caused by a difference in refractivity between the substrate100 and air outside the substrate 100. Namely, the light incident to thesubstrate 100 with an incidence angle larger than or equal to thetotal-reflection critical angle is lost without being extracted from thesubstrate 100.

However, since the organic light emitting diode display device,according to this embodiment, has an out-coupling structure in which thesecond electrode 340, which is a reflective electrode, has the multipleconcave portions 341 and the multiple convex portions 642 in thenon-emissive area NEA, light extraction efficiency may be enhanced.

Specifically, since the overcoat layer 610 has the depressions 517 inthe non-emissive area NEA, the second electrode 340 may have anout-coupling structure in which the second electrode 340 has themultiple concave portions 341 and the multiple convex portions 642 inthe non-emissive area NEA. Meanwhile, among the light emitted from theorganic light emitting element EL disposed in the emissive area EA,light incident to the substrate 100 with an incidence angle larger thanor equal to the total-reflection critical angle may be totally reflectedat the interface between the substrate 100 and air to reach the inclinedsurface of the second electrode 340 in the non-emissive area NEA(herein, the optical path does not vary much since the organic lightemitting layer 330 has a refractive index that is almost the same asthat of the second electrode 340). The light that reaches the inclinedsurface of the second electrode 340 in the non-emissive area NEA may bereflected by the second electrode 340, which is a reflective electrode,and may be input to the substrate 100 with an incident angle smallerthan or equal to the total-reflection critical angle so as to beextracted from the substrate 100.

Meanwhile, the height of the depressions 517 provided in the overcoatlayer 610 may be the same as the vertical length of the overcoat layer610 in the non-emissive area NEA. Namely, the depressions 517 may bedisposed to expose the surface of the substrate 100 as illustrated inFIG. 14. However, this embodiment is not limited thereto, and in a casewhere other insulation layers are disposed between the substrate 100 andthe overcoat layer 610, the depressions 517 of the overcoat layer 610may be disposed to expose the surface of an insulation layer adjacent tothe overcoat layer 610.

Since the height of the depressions 517 of the overcoat layer 610 is thesame as the vertical length of the overcoat layer 610 provided in thenon-emissive area NEA, the surface areas of the inclined surfaces 611 ofthe overcoat layer 610, which are provided by the depressions 517,become large. Accordingly, the surface area of the second electrode 340,which is disposed on the inclined surfaces 611 of the overcoat layer610, also becomes large so that it is possible to effectively reflectlight travelling toward another emissive area EA that is adjacent tolight totally reflected at the interface between the substrate 100 andair.

In other words, when the second electrode 340 has a large surface area,the area by which the light totally reflected at the interface betweenthe substrate 100 and air may reach the second electrode becomes larger,and the area by which the light travelling toward the adjacent emissivearea EA may reach the second electrode 340 becomes larger than when thesecond electrode 340 has a small surface area, which makes it possibleto extract a larger amount of light from the substrate 100.

As described above, the organic light emitting diode display device,according to this embodiment, reflects light incident to the substrate100 with an incidence angle larger than or equal to the total-reflectioncritical angle among the light emitted from the organic light emittingelement EL by using the second electrode 340 having the inclinedsurfaces disposed in the non-emissive area NEA to extract the reflectedlight from the substrate 100, thereby enhancing the light-emittingefficiency of the organic light emitting diode display device.

In addition, among light emitted from the organic light emitting elementEL outside an emissive area EA, light output toward another adjacentemissive area EA is reflected by means of the second electrode 340having inclined surfaces disposed between the different emissive areasEA and is extracted from the substrate 100. Accordingly, it is possibleto prevent a light leakage phenomenon between sub-pixels, which iscaused by light travelling toward the adjacent emissive area EA.

While the depressions 517 of the overcoat layer that are providedadjacent to the individual emissive areas EA have the same size in theorganic light emitting diode display device, according to the fourthembodiment (see FIG. 13), the present invention is not limited thereto,and depressions may have different sizes as illustrated in FIG. 15. Thisconfiguration will be described below in detail with reference to FIG.15.

FIG. 15 is a plan view of an organic light emitting diode display deviceaccording to a fifth embodiment of the present invention. The organiclight emitting diode display device, according to the fifth embodimentof the present invention, may include the same elements as those of theorganic light emitting diode display devices in the aforementionedembodiments. Repetitive descriptions identical to ones given in theaforementioned embodiments will be omitted. Also, identical elements areprovided with identical reference numerals.

Referring to FIG. 15, the organic light emitting diode display device,according to the fifth embodiment, may include an overcoat layer thathas multiple depressions 517 and 518 in a part of a non-emissive areaNEA. In this case, the multiple depressions 517 and 518 provided in thenon-emissive area NEA may have different sizes.

For example, a first depression 518 disposed adjacent to one emissivearea may be larger in size than a second depression 517 disposedadjacent to another emissive area. For example, the first depression 518may be wider than the second depression 517. This may help to enhancethe light extraction efficiency of an emissive area that has lower lightextraction efficiency than other emissive areas.

While the first depression 518 and the second depression 517 areillustrated in FIG. 15 as corresponding to partial areas outsideemissive areas, this embodiment is not limited thereto, and the firstdepression 518 or the second depression 517 may be provided to surroundthe emissive areas.

Next, an organic light emitting diode display device, according to asixth embodiment of the present invention, will be described below withreference to FIG. 16. FIG. 16 is a plan view of the organic lightemitting diode display device according to the sixth embodiment of thepresent invention. The organic light emitting diode display device,according to the sixth embodiment, may include the same elements asthose of the organic light emitting diode display devices in theaforementioned embodiments. Repetitive descriptions identical to onesgiven in the aforementioned embodiments will be omitted. Also, identicalelements are provided with identical reference numerals.

Referring to FIG. 16, in the organic light emitting diode displaydevice, according to the sixth embodiment, depressions 517 of anovercoat layer may be provided only in areas that correspond to theouter periphery of a particular emissive area in one pixel P.Specifically, in the organic light emitting diode display device,according to the sixth embodiment, the depressions 517 of the overcoatlayer may be provided only in areas that correspond to the outerperiphery of a particular area of a plurality of emissive areas providedin one pixel P and may not be provided in areas that correspond to theouter peripheries of the remaining emissive areas.

This may help to enhance the light extraction efficiency of a desiredemissive area. Namely, the organic light emitting diode display device,according to the sixth embodiment, may adjust light extractionefficiency in units of emissive areas through the depressions 517 of theovercoat layer.

Next, one pixel of an organic light emitting diode display device towhich a sub-pixel, according to an embodiment of the present invention,is applied will be hereinafter described. FIG. 17 is a sectional view ofthe pixel of the organic light emitting diode display device to whichthe sub-pixel, according to the embodiment of the present invention, isapplied.

The organic light emitting diode display device of FIG. 17 may includethe same elements as those of the organic light emitting diode displaydevices in the aforementioned embodiments. Repetitive descriptionsidentical to ones given in the aforementioned embodiments will beomitted. Also, identical elements are provided with identical referencenumerals.

Referring to FIG. 17, one pixel P of the organic light emitting diodedisplay device, to which the sub-pixel according to the presentinvention is applied, includes four sub-pixels. While the pixel P isillustrated in FIG. 17 as including four sub-pixels, the presentinvention is not limited thereto, and the pixel P may include two orthree sub-pixels.

In FIG. 17, the pixel P may include four sub-pixels, and each sub-pixelmay include one emissive area EA and one non-emissive area NEA. Herein,multiple micro lenses are arranged in each emissive area EA on anovercoat layer 110, and multiple depressions 117 are arranged in eachnon-emissive area NEA on the overcoat layer 110. Further, a firstelectrode 120 of an organic light emitting element EL is disposed on afirst substrate 100 on which the multiple micro lenses and the multipledepressions 117 are arranged.

In this case, the first electrode 120 may be disposed in the emissivearea EA and in a part of the non-emissive area NEA. Although the firstelectrode 120 is illustrated in FIG. 13 as being disposed within themultiple depressions 117, the arrangement of the first electrode 120 ofthe organic light emitting diode display device, according to thepresent invention, is not limited thereto, and the first electrode 120may be disposed within only some of the multiple depressions 117, or maybe disposed only in the emissive areas EA.

A bank pattern 150 is disposed to fill the multiple depressions 117. Inthis case, the bank pattern 150 may be formed of an opaque organicmaterial. When light emitted from the organic light emitting element ELtravels toward an adjacent sub-pixel, the bank pattern 150 may serve toabsorb the light in order to prevent the light from reaching thedifferent adjacent sub-pixel.

Meanwhile, this embodiment is not limited thereto, and the bank pattern150 may have a shape that corresponds to the morphology of the multipledepressions 117. In this case, although not illustrated in the drawing,the first electrode 120 of the organic light emitting element EL mayalso be configured to correspond to the morphology of the multipledepressions 117. Furthermore, the first electrode 120 may be provided soas to be superposed on all the multiple depressions 117, but not some ofthe multiple depressions 117. However, the first electrode 120 may notbe provided at the boundary between the sub-pixels.

As described above, in the organic light emitting diode display devices,according to the embodiments of the present invention, the overcoatlayer in the non-emissive area NEA has at least one depression, and thebank pattern is provided so as to be superposed on the depression, whichmakes it possible to prevent light emitted from the organic lightemitting element from travelling toward a sub-pixel emitting lighthaving a different color to cause a light leakage phenomenon.

In addition, in the organic light emitting diode display devices,according to the embodiments of the present invention, the overcoatlayer in the non-emissive area NEA has at least one depression, and thereflective electrode is disposed along the shape of the depression,which makes it possible to absorb light travelling toward a sub-pixelthat emits light having a different color, among light emitted from anorganic light emitting element, thereby preventing light leakage, or toreflect the light travelling toward the sub-pixel, thereby enhancinglight extraction efficiency.

Particular characteristics, structures, or effects described inconnection with the embodiments are included in at least one embodimentof the present invention and not necessarily in all embodiments.Furthermore, the particular characteristics, structures, or effects ofany specific embodiment of the present invention may be combined in anysuitable manner with one or more other embodiments or may be changed bythose skilled in the art to which the embodiments pertain. Therefore, itis to be understood that contents associated with such combination orchange fall within the spirit and scope of the present invention.

Although the present invention has been described with reference to someexemplary embodiments, it should be understood that these embodimentsare given by way of illustration only and do not limit the scope of theinvention, and that various modifications, variations, and alterationscan be made by those skilled in the art without departing from thespirit and scope of the invention. For example, the componentsspecifically shown in the embodiments can be modified.

What is claimed is:
 1. An organic light emitting diode display devicecomprising: a substrate divided into an emissive area and a non-emissivearea; an overcoat layer disposed on the substrate and having a pluralityof micro lenses in the emissive area and at least one depression in thenon-emissive area, each of the plurality of micro lenses comprising aconcave portion and a connecting portion; a first electrode disposed onthe overcoat layer; a bank pattern disposed in the non-emissive area soas to be superposed on the at least one depression; an organic lightemitting layer disposed on the first electrode; and a second electrodedisposed on the organic light emitting layer.
 2. The organic lightemitting diode display device of claim 1, wherein the bank pattern isdisposed to fill the at least one depression.
 3. The organic lightemitting diode display device of claim 2, wherein the bank pattern isformed of an opaque organic material.
 4. The organic light emittingdiode display device of claim 1, wherein a height of the at least onedepression is less than a vertical length of the overcoat layer in thenon-emissive area.
 5. The organic light emitting diode display device ofclaim 1, wherein a height of the at least one depression is the same asa vertical length of the overcoat layer in the non-emissive area.
 6. Theorganic light emitting diode display device of claim 1, wherein thefirst electrode is disposed within the at least one depression, and thebank pattern is disposed on the first electrode.
 7. The organic lightemitting diode display device of claim 6, wherein the organic lightemitting layer and the second electrode are disposed on the bankpattern, and the second electrode is a reflective electrode.
 8. Theorganic light emitting diode display device of claim 1, wherein theovercoat layer has at least one step in the non-emissive area or in theemissive area adjacent to the non-emissive area.
 9. The organic lightemitting diode display device of claim 8, wherein the overcoat layercomprises a protruding portion provided between the at least one stepand the at least one depression located adjacent to the at least onestep, and a height from the concave portion to the connecting portion ofeach of the plurality of micro lenses is less than a height from theconcave portion of each of the plurality of micro lenses to theprotruding portion of the overcoat layer.
 10. The organic light emittingdiode display device of claim 9, wherein the position of a first organiclight emitting element disposed on the connecting portion is lower thanthat of the first electrode of a second organic light emitting elementdisposed on the protruding portion.
 11. The organic light emitting diodedisplay device of claim 9, wherein the first electrode of the secondorganic light emitting element extends to at least a part of theprotruding portion.
 12. The organic light emitting diode display deviceof claim 11, wherein the first electrode of the second organic lightemitting element is a reflective electrode.
 13. The organic lightemitting diode display device of claim 11, wherein the first electrodeof the second organic light emitting element is formed of a transparentconductive material, and a reflective layer is disposed below the firstelectrode of the second organic light emitting element in the same formas that of the first electrode.
 14. An organic light emitting diodedisplay device comprising: a substrate having a plurality of emissiveareas and a non-emissive area that surrounds the plurality of emissiveareas; an overcoat layer disposed on the substrate and having aplurality of micro lenses in each emissive area and at least onedepression in the non-emissive area, each of the plurality of microlenses comprising a concave portion and a connecting portion; a firstelectrode disposed on the overcoat layer in the plurality of emissiveareas; an organic light emitting layer disposed on the first electrode,the overcoat layer, and the at least one depression; and a secondelectrode disposed on the organic light emitting layer.
 15. The organiclight emitting diode display device of claim 14, wherein a height of theat least one depression is the same as a vertical length of the overcoatlayer in the non-emissive area.
 16. The organic light emitting diodedisplay device of claim 14, wherein the second electrode comprises atleast one concave portion and at least one convex portion in thenon-emissive area.
 17. The organic light emitting diode display deviceof claim 16, wherein the at least one concave portion of the secondelectrode is provided in an area that corresponds to the at least onedepression of the overcoat layer.
 18. The organic light emitting diodedisplay device of claim 14, wherein the at least one depression isprovided in an area that corresponds to at least one side of at leastone of the plurality of emissive areas.
 19. The organic light emittingdiode display device of claim 14, wherein a first depression provided inan area corresponding to one side of at least one of the plurality ofemissive areas has a different size from that of a second depressionprovided in an area corresponding to one side of each of the remainingplurality of emissive areas.
 20. The organic light emitting diodedisplay device of claim 14, wherein the second electrode is a reflectiveelectrode.